Earth wire for a ceiling fan

[psarinuk]

Hello all,

I've bought 2 smallish and very light weight ceiling fans from B&Q with lights (called Twister) for first floor bedrooms.

The existing wiring for lights does not have earth (old wiring).
So I am thinking of running an extra earth cable to loft as the manual for fan says that I need to earth them.

Question is where should the earth be connected? I cannot find a suitable earth point in the loft (only wood, insulation and bricks available). Should I run it all the way down to the consumer unit?

The earth at consumer unit (@ ground floor kitchen) is connected to a copper pipe (under kitchen sink and the mains gas pipe (under the consumer unit) so both are quite far too.

I do have a CH expansion tank with an overflow copper pipe just under the loft in the airing cupboard but not sure if I can use that?

Just need some guidance here.
Thanks for your help in advance.

 

[EFLImpudence]

Should I run it all the way down to the consumer unit?

Yes, if you can do that you should run a new cable which you can use to upgrade other lights if and when you need.

I do have a CH expansion tank with an overflow copper pipe just under the loft in the airing cupboard but not sure if I can use that?

No.

 

[Simon35]

Hello all,

I've bought 2 smallish and very light weight ceiling fans from B&Q with lights (called Twister) for first floor bedrooms.

The existing wiring for lights does not have earth (old wiring).
So I am thinking of running an extra earth cable to loft as the manual for fan says that I need to earth them.

Question is where should the earth be connected? I cannot find a suitable earth point in the loft (only wood, insulation and bricks available). Should I run it all the way down to the consumer unit?

The earth at consumer unit (@ ground floor kitchen) is connected to a copper pipe (under kitchen sink and the mains gas pipe (under the consumer unit) so both are quite far too.

I do have a CH expansion tank with an overflow copper pipe just under the loft in the airing cupboard but not sure if I can use that?

Just need some guidance here.
Thanks for your help in advance.

Also, if it has no mechanical protection i.e conduit, trunking etc, then it needs to be 4mm cable.

 

[JohnW2]

Also, if it has no mechanical protection i.e conduit, trunking etc, then it needs to be 4mm cable.

Indeed - and even if it does have 'mechanical protection' it is still required to be at least 2.5mm².

In passing .... I must confess that I have never really understood these minimum CSA requirements for 'separate protective conductors' - particularly given that the issue most often arises (as in this thread) in relation to adding a CPC to a lighting circuit, which would only require a 1mm² if it were included within a T+E cable. In the absence of mechanical protection, their concern may relate to mechanical damage, with them using conductor CSA as a surrogate for 'resistance to mechanical damage' - but even that's a bit odd, given that, say, a 1mm² insulated+sleeved conductor (without any mechanical protection) might well be acceptable for the live conductors of the same circuit. However, if the conductor is 'mechanically protected', I don't really understand why one has to use a 2.5mm² conductor if, for example, the electrical requirement is only for a 1mm² CPC for the circuit concerned. Any thoughts?

Kind Regards, John

 

[ericmark]

50 meters 1mm twin and earth £18.45 100 meters of 4mm earth cable £54.41 so why run in an earth rather than change whole cable and do the job correctly?

 

[Simon35]

Also, if it has no mechanical protection i.e conduit, trunking etc, then it needs to be 4mm cable.

Indeed - and even if it does have 'mechanical protection' it is still required to be at least 2.5mm².

In passing .... I must confess that I have never really understood these minimum CSA requirements for 'separate protective conductors' - particularly given that the issue most often arises (as in this thread) in relation to adding a CPC to a lighting circuit, which would only require a 1mm² if it were included within a T+E cable. In the absence of mechanical protection, their concern may relate to mechanical damage, with them using conductor CSA as a surrogate for 'resistance to mechanical damage' - but even that's a bit odd, given that, say, a 1mm² insulated+sleeved conductor (without any mechanical protection) might well be acceptable for the live conductors of the same circuit. However, if the conductor is 'mechanically protected', I don't really understand why one has to use a 2.5mm² conductor if, for example, the electrical requirement is only for a 1mm² CPC for the circuit concerned. Any thoughts?

Kind Regards, John

My thoughts are that terminating a 4mm earth cable in a "smallish and very light weight ceiling fans from B&Q with lights (called Twister)" might drive him round the twist....

 

[JohnW2]

50 meters 1mm twin and earth £18.45 100 meters of 4mm earth cable £54.41 so why run in an earth rather than change whole cable and do the job correctly?

Agreed. If the intention were to (as it should be done) run an earth/CPC all the way back to the CU, then it would make little or no sense to do that, rather than running a new T+E. Of course, there would probably be a need for some changes to the configuration of the circuit (and maybe upgrade other cables to T+E), since, unless the OP is very lucky, the place in the lighting circuit he wants to get the fan feed from will probably not be connected directly to the CU. The ideal, of course, would be to upgrade the whole circuit to T+E.

Kind Regards, John

 

[JohnW2]

My thoughts are that terminating a 4mm earth cable in a "smallish and very light weight ceiling fans from B&Q with lights (called Twister)" might drive him round the twist....

Yep, that too. I suppose there is nothing to stop one taking the 4mm to a JB where it meets up with a short length of T+E (or even flex) - the 1mm² (or whatever) CPC (with minimal mechanical protection) of which appears to be acceptable to the regs!

Kind Regards, John

 

[psarinuk]

Thanks for your replies folks.

There are 2 lighting circuits at the CU: One for first floor and one for ground floor.
The upstairs one where the fans are to be installed will be upgraded to NEW 1.5 T&E all the way from the CU. The access is feasible through an empty loft.

The downstairs lighting cannot be upgraded yet (3 lights only) due to nice wood flooring (nailed) installed in all the rooms (on first floor).

 

[ban-all-sheds]

Ah - nothing like planning ahead, and making sure that electrical installation components you are about to make inaccessible don't need any attention before being made inaccessible.

 

[JohnW2]

There are 2 lighting circuits at the CU: One for first floor and one for ground floor. The upstairs one where the fans are to be installed will be upgraded to NEW 1.5 T&E all the way from the CU. The access is feasible through an empty loft.

That's the best solution. Are you going to replace all the cables in that circuit with T+E? 1mm² T+E would almost certainly be adequate.

The downstairs lighting cannot be upgraded yet (3 lights only) due to nice wood flooring (nailed) installed in all the rooms (on first floor).

Although obviously not ideal (and certainly not compliant with current regulations - although there is no requirement to comply with them retrospectively) that is not a major issue provided that all of your switches are light fittings etc. are plastic. If any are metal, they would have to be earthed, so you would have a problem.

Kind Regards, John

 

[psarinuk]

Hi John

Yes all the first floor lighting would be replaced by new T&E wiring from the CU.

I am kicking myself for not being able to do much about ground floor lighting.

I've opened to check all the ground floor lights and switches. I covered the exposed wires with insulation tape and correct colored sleeves as extra protection. The wiring still inside the outer PVC insulation looks good.

Also as you say, all switches are plastic.

 

[JohnW2]

Hi John Yes all the first floor lighting would be replaced by new T&E wiring from the CU. I am kicking myself for not being able to do much about ground floor lighting.

Fair enough.

I've opened to check all the ground floor lights and switches. I covered the exposed wires with insulation tape and correct colored sleeves as extra protection. The wiring still inside the outer PVC insulation looks good.

What are these 'exposed wires'?

Also as you say, all switches are plastic.

That's good - and the light fittings, too?

Kind Regards, John

 

[psarinuk]

What are these 'exposed wires'?

The exposed wires were the wires (not bare copper) that have been taken out of outer PVC insulation in red and black plastic. The quality of plastic on these wires was not great really, so I covered all of them to get more life.

That's good - and the light fittings, too?

Hmmm.. I've one batten in kitchen and 2 lights in the living room. The lights in the living room are made of glass but the plate that hangs the glass to the ceiling and holds the connector is metallic.. The connectors and wires are all covered with insulation tape.

 

[ban-all-sheds]

The quality of plastic on these wires was not great really, so I covered all of them to get more life.

Insulating tape isn't insulating - if the insulation on the conductors was damaged then you should have used sleeving, not tape. The tape will also fall off in the not too distant future.